Vacuuming skin packaging (VSP) process is well known in the art and various apparatus and processes have been described, for example, in U.S. Pat. Nos. 3,835,618; 3,950,919 and Re 30,009, all issued to Perdue. The vacuum skin packaging process is in one sense a type of thermoforming process in which an article to be packaged serves as the mold for the thermoform. An article may be placed on a support member, such as a rigid or semi-rigid card, tray or other bottom support member; the supported article is then passed to a chamber where a film can be either heated and draped over the article, or drawn upwards against a heated dome and then, draped over the article. The movement of the film may be controlled by vacuum and/or air pressure; and in a vacuum skin packaging arrangement, the interior of the container may be evacuated before final sealing of the film to the support. Typically, thermoformable materials may be used as the draping film. Examples of vacuum skin packaging trays, films and processes are disclosed in U.S. Pat. Nos. 4,611,456 to Gillio-tos et al.; 5,846,582 to Mayfield et al.; and 5,916,613 to Stockley Ill., which are hereby incorporated by reference herein.
Vacuum skin packaging applications may include packaging of perishable or non-perishable food products, such as, e.g., fresh red meat and sliced cheese, or frozen food products, such as frozen fish, poultry and the like. Typically, the packaging material for oxygen-sensitive food and non-food products require lower oxygen permeability compare to that for non-oxygen sensitive products. For example, U.S. Patent Application Publication No. 2006/0269707 to Otacilio Berbert, the disclosure of which is hereby incorporated herein by reference, describes several multilayer thermoformable films suitable for use in vacuum skin packaging applications of perishable food products. The disclosure demonstrates that VSP films can be modified to provide an oxygen transmission rate of from about 0-2.0 cm3/100 in2/24 hours at 0% R.H. and 23° C. These films include an oxygen barrier layer comprising ethylene/vinyl alcohol copolymer and a surface-treated sealing layer comprising polyethylene vinyl acetate copolymer.
Generally, labels and printed indicia are located on a package where it may be viewed by the consumer. Typically, these markings are positioned on a relatively smooth, flat upper surface of the package which allows the consumer to read product information without having to handle the package. Indicia on vacuum skin packages become illegible when located on the upper surface of the packaging film formed to an irregularly shaped product. For this reason, vacuum skin packaging often includes an over-packaging technique, e.g., the use of an overwrap film, a paperboard sleeve or a carton box, which covers the vacuum skin package and provides a flat surface for printed information. However, over-packaging is an extra cost to the manufacturer, and labels and other printed information applied underneath the package are not attractive to consumers who are accustomed to viewing the product and product information together.
Thus, it is an object of the present invention to overcome the labeling difficulties of the prior art.
It is also an object of the present invention to provide a flexible packaging laminate for vacuum skin packaging applications.
It is also an object of the present invention to provide a flexible packaging laminate which separates into two films when subjected to heat and differential air pressure thereby forming a substantially horizontal first film-surface above a product and a thermoformable second film-surface enclosing the product.
It is yet another object of the present invention to provide a vacuum skin package.
It is yet another object of the present invention to provide a vacuum skin package which provides a substantially horizontal film-surface disposed above the product and a thermoformed film-surface surrounding the exterior shape of the product.
It is yet still another object of the present invention to provide a method of vacuum skin packaging a product using a single flexible laminate.